Pick is already on 159 in the Channel Islands and nothing is on 159 or 160 anywhere in the UK so moving them here seems the obvious choice.
Slightly off-topic, apologies, but why isn't Pick on 152 in the Channel Islands?
159 (and 160) were previously owned by Viacom and used for 5Select and VH1. Both became empty in January when 5Select moved to 153 and VH1 closed. Sky bought the slots but had to use them, as an EPG
slot is lost if it isn't used within a certain timeframe.
Pick was put on 159 in the Channel Islands to keep that slot active, and Viacom's Smithsonian had a very short spell on 160 to keep that alive.